Ceilings come in a variety of different configurations with one form of ceiling that is quite common, especially in office environments, being a dropped ceiling with ceiling tiles held in place by T-bars. The dropped ceiling is oriented in a plane parallel with the floor and suspended beneath a utility space within which HVAC, electrical, telephone and other utilities can be conveniently located.
The T-bars, in a simplest form, have a planar lower leg and a planar upper leg perpendicular to the lower leg and intersecting with the lower leg at a midpoint thereof. The lower surface of the lower leg faces downward. Portions of the lower leg on either side of the upper leg present shelves upon which ceiling tile edges can rest. The T-bars are arranged, typically in a grid pattern. This grid pattern can be made up of squares or rectangles (or other shapes). In a uniform grid ceiling, the ceiling tiles are in the form of squares with each edge of the ceiling tile supported upon an adjacent T-bar lower leg.
To form the grid of T-bars, typically T-bars running in a first direction are long T-bars, such as long enough to span an entire room (or as far as possible in a larger room where it is impractical to have T-bars spanning the entire length of the room). In a second direction perpendicular to the first direction, shorter T-bars are located which merely extend between adjacent long T-bars. In addition to supporting ceiling tiles, the T-bars can also support air conditioning returns and registers, as well as light fixtures and other equipment. The upper leg of each T-bar has holes periodically passing therethrough through which wire or other suspension elements can connect to support the suspended ceiling array of T-bars at the desired elevation above the floor.
One form of T-bar known in the prior art includes lighting built into the lower leg of the T-bar. One such LED lighted T-bar is described in U.S. Pat. No. 8,177,385, incorporated herein by reference. With such a lighted T-bar, the lower leg is provided with a greater depth and LED lights are located within the lower leg, and typically with some form of diffuser element over a surface of the LED and between the LED and a lower surface of the lower leg. Most preferably, especially with high intensity LEDs, the upper leg of the T-bar is configured to include heat transfer fins so that heat can be effectively dissipated away from the LEDs and outside of an air conditioned space below the suspended ceiling and into the utility space above the suspended ceiling. Lighting is thus provided in linear sections along the T-bars.
In a ceiling with long T-bars extending in a first direction and short T-bars extending perpendicularly between the long T-bars, LED lighted T-bars can conveniently span the short distance between long T-bars to present lighting into the space adjacent the suspended ceiling. However, such a configuration only facilitates lighting oriented in a first direction perpendicular to the long T-bars. In many instances for either functional and/or aesthetic reasons, it is desirable to have lighted T-bar segments both parallel to the long T-bars and perpendicular to the long T-bars. Also, lights of various lengths would be beneficial. Accordingly, a need exists for partially lighted T-bars and shorter fully lighted T-bars to provide a larger variety of options to achieve functional and aesthetic goals in lighting a space beneath a suspended ceiling.